Amp/tube failure last night and why 100watt amps are better!

[Endtime]

Maybe you can suspect why. But.. around the 3rd song, which I open with a riff alone I noticed my sound was way off. I first suspected the stage monitor was toast cause it was CRANKED!. It actually sounded really good but I have had other monitors either blow or maybe they have overload protect circuit that trigger. Idk. But that was my initial assumption. I played for about 2 minutes I’d guess with this blown out wimpy sound in my monitor. Until I got a little whiff of what smelled like a tube burning up. . I’m like no way. But I did go back and check while playing and sure enough, it was like a mini Red sun back there on the far left tube. This is my 6505 and Sovtek 6l6wxt tubes which both have never red plated on me. That 6505 is as robust as it gets and so are those tubes. They aren’t new, but not too old. Just standard .

Welp, first idea is simply, shut er down pull the 2 outer tubes , cause the far left was the only one I saw redplating, and run it at 8 ohms. I let em finish the song before I hit it back off standby. And worked the rest of the night! I know that’s not some amazing tech fix, but still the fact it actually worked in the field is always a bit of satisfaction!

And you can’t do that with a 50watter!!

[Guitarbilly]

Hahaha yeah man, built-in backup. Do you leave the back open or did you have to remove it?

[Endtime]

Hahaha yeah man, built-in backup. Do you leave the back open or did you have to remove it?

Right? One way to word it , cause it did feel like my backup! Haha

I actually had the back on. Only amp of mine that I do. Cause when I put in the Mercury transformer it has wires coming out each “side”, so the the far side of the transformer has a little more wire exposed as it goes around the tranny into the opening of the chassis. So I always felt there’s a small chance something snags in those wires and I pull out one of the wires or sumthin. Since also the 6505 has hardwired power cord and the cord wrap is on the little grate to protect the tubes. So it makes more sense on that one to keep it on. But I carry a couple screwdrivers so no big deal.

[broslinger]

That’s awesome. I’m glad it worked out.

I’ve always kept that trick in the back of my mind. I learned it from a guitar world article when i was a noob back in the 90’s.

I hardly ever play gigs, and I’ve had issues the last two years.

[Endtime]

That’s awesome. I’m glad it worked out.

I’ve always kept that trick in the back of my mind. I learned it from a guitar world article when i was a noob back in the 90’s.

I hardly ever play gigs, and I’ve had issues the last two years.

Thanks man. And another reason to keep Guitar world in print Eh? Hah. Plus it’s funny what little tidbits stick. From the 90s!!

I knew it for troubleshooting certain things. It just started to smoke when I shut it down. And I know the old screen grid resistors on these amps would have blown. They used to be 100ohm and I guarentee this would have blown and took out the powerboard fuse which is in the amp. And if I’m literally have no option I could pull it apart and get in there in 5 minutes. But very unlikely I’d do that at a show. So the upgraded screen grids kept the amp working but I guess the trade off is I was maybe 30-60 seconds before shit may have actually started to get burned up and maybe arc and cause real damage.

I didn’t have any fuses anyway! So glad it hung on while she was burning down! Hah

[Guitarbilly]

I don't remember how thick the 6505 headshell is, but on my main DSL, I use velcro to hold the backplate in place instead of screws.
It makes this type of stuff a lot easier, but it doesn't work for every amp, it depends whether the inside of the headshell has enough surface contact with the back to give the velcro a good grip.

[Endtime]

Yeah that wouldn’t really work well for this. It’s literally just the metal grate. I believe the Marshall has a wood frame holding the grate. I think? Anyway, it’s 4 screws. Took no more than a minute to get those 4 out. And likely like 30 seconds. They are coarse thread 5/8th screws so just a few turns and each screw is out.

[macaronisalad]

That really is a good selling feature on a 100 watt amp. I had recently been thinking about getting a 100 watt something, and just running it with 2 tubes anyways. Of course the urge sort of passed, but it remains a good idea. And its nice to see it work in "real life"

[ninjaraf]

Nice! I would've forgotten all about this, but this might make me remember if this ever happens to me!

[JSutter]

I don't remember how thick the 6505 headshell is, but on my main DSL, I use velcro to hold the backplate in place instead of screws.
It makes this type of stuff a lot easier, but it doesn't work for every amp, it depends whether the inside of the headshell has enough surface contact with the back to give the velcro a good grip.

That's a good idea. There are many cabs and amps that use Velcro or Dual Lock to hold the grill on.